# [tmql-wg] Re: [tmcl-wg] TMPath - experiments summary

Dmitry dmitryv@cogeco.ca
Thu, 31 Jul 2003 11:15:48 -0400

From: "Robert Barta"
Sent: Thursday, July 31, 2003 12:01 AM
Subject: Re: [tmcl-wg] TMPath - experiments summary

> Dmitry,
>
> Sorry that it took so long to respond to that, but I have been under some
> recently. I analysed this with great interest, especially since there are
some
> similarities with what I tried with AsTMaPath
>
>   http://astma.it.bond.edu.au/astma%3F-spec.dbk?section=10

reuse as much as I can from AsTMa? :-)
My original goal was to investigate functional, "XPath"-style language which
can be embedded into other constructs such as TMCL.
So I tried to stay on "pure" functional ground.

> - I think languages like these will not only be necessary for
> TMQL/TMCL but also for the TM update language (TMUL? :-).
>
> - The fact that you have a loop, if and quantifiers in the
> language makes it a complete query language if we ignore the
> content generation part (and some bells and whistles
> necessary).

My main interest was TMCL. For TMCL I tried to find equivalent of FOL
functors. I think that "path" expressions can play this role very well.
For TMCL my plan is to have "pure" assertion-based language vs pattern-based
language.

Currently I try to extend TMPath with pluggable serializers. Two samples for
XML and Wiki:
http://homepage.mac.com/dmitryv/TopicMaps/TMPath/TMPathSerializerSamples.txt

> Lars is usually concerned that predicates together with navigation
> overlap with the pattern matching approach making the language
> non-orthogonal. Using Perl a lot has taught me that exactly this
> overlap can make a language VERY handy, so I am not so overly worried
> as long as this can be orthogonalized underneath (for describing the
> semantics). Developer convenience is a higher good for me.

> What I probably want to say is that theoretically - as you have done
> it - it should be possible to do _everything_ with path expressions. I
> find pattern a bit more readable, though, because I can bind several
> variables at once.

> \rho

I guess different developers prefer different language styles. I am
originally from LISP camp... So I just prefer "look and feel" of XSLT and
XPath

Thank you,

Dmitry